[gnome-nibbles/arnaudb/kill-preferences-dialog: 23/27] Fix Preferences dialog background color.

[Arnaud B. <arnaudb src gnome org>]

commit 7057e0ba3cd4eeef6fe26dec4f85e1907f2aa73b
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Fri Jun 19 16:30:37 2020 +0200

    Fix Preferences dialog background color.

 data/nibbles.css   | 2 +-
 data/ui/nibbles.ui | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/data/nibbles.css b/data/nibbles.css
index 8bdcfb3..7facddf 100644
--- a/data/nibbles.css
+++ b/data/nibbles.css
@@ -1,4 +1,4 @@
-window {
+window.nibbles-window {
   background-color: rgba(0, 0, 0, 1);
 }
 
diff --git a/data/ui/nibbles.ui b/data/ui/nibbles.ui
index 7f00add..3cd4523 100644
--- a/data/ui/nibbles.ui
+++ b/data/ui/nibbles.ui
@@ -51,6 +51,9 @@
   <template class="NibblesWindow" parent="GtkApplicationWindow">
     <!-- Translators: title of the window, as displayed by the window manager -->
     <property name="title" translatable="yes">Nibbles</property>
+    <style>
+      <class name="nibbles-window"/>
+    </style>
     <child type="titlebar">
       <object class="GtkHeaderBar" id="headerbar">
         <property name="visible">True</property>